It's shown in OALD that
spend something doing something
spend something in doing something
Oxford Advanced Learner's Dictionary 9th edition © Oxford University Press, 2015
However, I've come across 2 sentences that break those rules
She carries herself erectly, despite having spent the day bent over an ironing board [...]
Millions of students in rural India spend their day bent over their books due to lack of classroom [...]
Why are they bent instead of bending? Are they cases of passive voice? If so, why is passive voice used in those cases ?